A 20-year dream to build a memorial to Martin Luther King Jr on the national mall in Washington moved a million steps closer to reality yesterday in Miami.

A $1m (£676,340) donation from the John S and James L Knight Foundation pushed the effort to honour the slain civil rights leader over the milestone $100m mark - and supporters are launching a campaign, with help from former President Bill Clinton and the Miami Heat basketball team, that they hope will inspire others to at least match that amount.

"We want to make this a dream for everybody in Miami," said Alberto Ibarguen, president and CEO of the Knight Foundation and a former publisher of the Miami Herald.

Harry Johnson, president and CEO of the Martin Luther King Jr National Memorial Project Foundation, said the south Florida support will help honour the black preacher of peace in a hallowed place previously reserved for presidents and soldiers.

A 28-foot (8.5-metre) statue, which depicts King emerging from a mountain of granite, will be the centrepiece of a four-acre memorial on the national mall's tidal basin - adjacent to the Franklin Roosevelt memorial and halfway between monuments to Thomas Jefferson and Abraham Lincoln.

"Can you imagine that?" Johnson said, during a news conference announcing the donation at the Adrienne Arsht Centre in Miami. "I always say it will be great to see a King sitting between two presidents."

In addition to the contribution, which put the Knight Foundation among some 40 foundations and corporations nationally that have donated $1m or more, the Knight Foundation will also host a January 8 fundraising "Miami Dream Dinner", featuring Clinton as keynote speaker, at the newly renovated Fontainebleau hotel in Miami Beach.

The former president, who signed a congressional resolution in 1998 authorising the memorial and has actively campaigned for it, will receive the King Memorial Foundation's humanitarian award.

The campaign also intends to raise awareness working with Miami-Dade schools and by airing videos during breaks at Miami Heat games.

They'll feature NBA legends such as Magic Johnson urging support for the memorial and include a tagline for fans to text donations from their seats in the AmericanAirlines Arena.

"If you feel inspired and the Heat are winning, you contribute another $5," Ibarguen laughed.

Ibarguen, who once interviewed King as a reporter for his university newspaper, The Wesleyan Argus in Connecticut, said he was hopeful that south Florida, home to a large number of minority populations that "hugely benefited" from King's groundbreaking civil rights activism, would embrace the project.

Support has already been strong. The local chapter of Alpha Phi Alpha, the nation's oldest black fraternity, which started the drive to honour King in the 1980s, has raised nearly $100,000. But nationally, despite the major corporate donations and a superstar list of black supporters, donations lagged enough to push opening dates back several times and several years.

But donations began rising in 2006 in the wake of the deaths of civil rights icons Rosa Parks and King's widow, Coretta Scott King. With the memorial foundation now closing in on its goal of $120 million, Johnson said work should begin "very soon", with a completion target of 2010.

Delay, it turns out, worked for the better, giving the project a powerful resonance with the prospect of President-elect Barack Obama dedicating a memorial to the man who helped pave the way for his election.